A ceramic via may be considered as an electrical conduit extending between multiple conductive layers contained within a ceramic substrate. It is important for proper ceramic via operation that a thin film stud which is in electrical connection with that ceramic via shall be precisely aligned relative to the ceramic substrate. Distortion of the ceramic substrate, however, typically occurs during the sintering phase of manufacturing, with the amount of distortion varying between ceramic substrates which are customarily produced in large numbers. This variable distortion causes the actual location of the ceramic via to be different from (offset about) the nominal design desired location for both the ceramic via and the thin film stud. The thin film stud is typically mounted at the design desired location.
Previously, to accommodate the above distortions, large capture (i.e., electrical contact) pads have been applied between each misaligned ceramic via and its associated thin film stud in order to provide the required electrical connection. The standardized capture pads therefore had to be sized large enough to encompass the largest potential displacement offset between the actual and the design desired location, for all of the ceramic vias in a given ceramic substrate, regardless of their individual displacements. The situation is further aggravated when multiple ceramic substrates are used because the capture pad now has to be sized large enough to provide electrical connection for the worst individual displacement in any one of the ceramic substrates.
The large capture pads become charged during operation of the associated electronic circuits and, in themselves, have the collective capability of producing high electrical capacitances. As the performance of the electronic circuits increases, and they become more densely packed and contain more electronic components (including ceramic vias), the overall effect of the capacitances so produced is to slow down the operation of, and possibly produce spurious or erroneous signals within, the electronic circuit.
It is evident that it would therefore be desirable to reduce the size of the capture pads associated with the ceramic vias of ceramic substrates. This would result in faster, more reliable, and more energy efficient responses within the overall electronic circuit. It would also reduce the valuable electronic circuit space required by the capture pad itself.